public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }


    System.Data.SqlClient.SqlConnection conn = null;
    System.Data.SqlClient.SqlCommand command = null;
    // Set connection string
    SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder
    {
        // set server
        DataSource = @"datasource name",
        // set database
        InitialCatalog = @"catalog name",
        // access the database using the existing windows security certificate
        IntegratedSecurity = true
    };

    private void Form1_Load(object sender, EventArgs e)
    {

        conn = new System.Data.SqlClient.SqlConnection(builder.ConnectionString);
        command = conn.CreateCommand();
        command.CommandText = "select id,name from dbo.tabletest where id<>20 order by id desc ";

        // Start
        SqlDependency.Start(builder.ConnectionString);
        // Get data
        GetData();
    }

    private void GetData()
    {
        command.Notification = null;
        SqlDependency dependency = new SqlDependency(command);
        dependency.OnChange += new OnChangeEventHandler(sqlDependency_OnChange);

        using (SqlDataAdapter adapter = new SqlDataAdapter(command))
        {
            System.Data.DataSet ds = new DataSet();
            adapter.Fill(ds, "test");
            dataGridView1.DataSource = ds.Tables["test"];
        }

    }

    void sqlDependency_OnChange(object sender, SqlNotificationEventArgs e)
    {
        // Because it is a child thread, you need to update the ui with the invoke method.
        if (this.InvokeRequired)
        {
            this.Invoke(new OnChangeEventHandler(sqlDependency_OnChange), new object[] { sender, e });
        }
        else
        {
            SqlDependency dependency = (SqlDependency)sender;
            dependency.OnChange -= sqlDependency_OnChange;
            // After the notification, the current dependency is invalid, you need to re-get the data and set the notification.
            GetData();
        }
    }

    private void Form1_FormClosed(object sender, FormClosedEventArgs e)
    {
        // Clear resource
        SqlDependency.Stop(builder.ConnectionString);
        conn.Close();
        conn.Dispose();
    }
}

Result: